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Assembly Source File | 1987-03-12 | 22.0 KB | 471 lines

TITLE WalkTree - Execute Program at Every Level of Tree ; Copyright Notice: ; ; The program WalkTree, both in binary executable and source forms, is ; in the public domain. No warranty is given or implied, and no ; liability will be assumed by the author. ; ; Everyone on earth is hereby given permission to use, copy, distribute, ; change, mangle, destroy or otherwise employ these programs, in whole ; or in part, in any fashion they so desire, provided they hurt no one ; but themselves in the process. ; ; If anyone has any questions about this or any other program that I ; have authored, I can be reached by messages on any of the following ; systems: ; ; Bob's Answering Machine (602) 242-3158 300/1200 bps ; FIDO 114/1 Phoenix Node (602) 242-5230 300/1200/2400 bps ; FIDO 114/446 XTRA #1 (602) 979-6352 300/1200/2400 bps ; Technoids Anonymous (602) 899-4876 300/1200/2400 bps ; ; All excellent 24 hour systems. ; ; Don A. Williams ; 3913 W. Solano Dr. N. ; Phoenix, AZ 85019 ; This version of the source for WalkTree has been set up for assembly by ; SpeedWare's very good TurboEditAsm. To convert it for assembly by ; Microsoft's MASM will require the addition of Segment and Assume ; statements, at least. ; ; ; version history ; modified by John Covici ; 3 Wirt Street NW ; Leesburg, VA 22075 ; March 12, 1987 fixed the following bugs: ; (1) append cr to generated command line (if not dos goes out to lunch) ; (2) now assembles with masm ; (3) to get environment segment had to say [ds:2ch] instead of [2ch] ; otherwise assembler ignored brackets without error LF EQU 0AH ; ASCII Line Feed CR EQU 0DH ; ASCII Carriage Return cseg segment para public 'code' ORG 0100H assume cs:cseg,ds:cseg,ss:cseg Start: jmp Begin ; Jump over data area ;------ Messages LogOn db 'WalkTree: Version 1.01 - March 12, 1987',CR,LF,LF,'$' BadVer db 'WalkTree requires Dos 2.0 or greater',CR,LF,'$' UseMsg db 'USAGE: WalkTree <any dos command>',CR,LF,'$' EndMs1 db CR,LF,'Number of directories= $' EndMs2 db ': Maximum depth= $' EndMsg db '$' AbtMsg db 'Program terminated by operator.',CR,LF,'$' ;------ Constants and Other Data Storage Path db 0,':\',65 DUP(0) PatMsg db CR,LF,LF,'---' CurPat db 0,':\',65 DUP(0) PatTer db '---',CR,LF,0 MatAll db '*.*',0 Parent db '..',0 CmdTail db 0,'/c ' CmdLin db 128 DUP(0) ComSpc db 'COMSPEC',0 ComCom db '\COMMAND.COM',0 DTAOfs dw 0 ; Save space for DTA: Offset and DTASeg dw 0 ; ... Segment SaveSS dw 0 ; Save space for Stack; Segment and SaveSP dw 0 ; ... Pointer Level dw 0 ; Current depth in hierarchy MaxLev dw 0 ; Maximum depth in hierarchy DirCnt dw 0 ; Count of directories processed comand db 65 dup(0) ;space for command.com from env or default ;------ Parameter Block for DOS function 4B, Exec ParBlk dw 0 ; Seg of environment string dw 0 ; Ofs of Command Tail string dw 0 ; Seg " " " " dw 0 ; Ofs of Default FCB 1 dw 0 ; Seg " " " " dw 0 ; Ofs of Default FCB 2 dw 0 ; Seg " " " " ;========================================================================= ; Beginning of Program Code Begin: mov SP,offset STACK ; Set local stack cld ; Clear Direction Flag [forward] mov DX,offset LogOn ; Dsiplay logon message mov AH,9 ; ... MS-DOS 'Print String' int 21H ; ... DOS Entry Interrupt mov AH,30H ; MS-DOS 'Get Version' int 21H ; ... DOS Entry Interrupt cmp AL,2 ; Check for 2.x or greater jnb VerOk ; ... Xfr- 2.x or greater mov DX,offset BadVer ; Get ptr to 'bad version' msg ErrorExit: mov AH,9 ; MS-DOS 'Print String' int 21H ; ... DOS Entry Interrupt int 20H ; DOS Terminate Program Interrupt VerOk: mov AH,19H ; MS-DOS 'Get Current Disk' int 21H ; ... DOS Entry Interrupt add AL,'A' ; Convert disk code to alpha disk mov Path,AL ; ... and save in Path mov CurPat,AL ; ... and in Current Path mov SI,offset Path+3 ; Get Current Dir as starting path mov DL,0 ; ... current disk mov AH,47H ; ... MS-DOS 'Get Current Directory' int 21H ; ... DOS Entry Interrupt mov SI,80H ; Get ptr to Command Line buffer lodsb ; ... and get length or AL,AL ; Check for length zero - no tail jnz HaveTail ; ... Xfr - length not zero Usage: mov DX,offset UseMsg ; Display 'Usage' message and jmp short ErrorExit ; ... terminate HaveTail: cbw ; Make length 16 bits mov CX,AX ; ... and move to CX for move add AL,3 ; Adjust length for '/c ' mov CmdTail,AL ; ... and store for DOS 4BH mov DI,offset CmdLin ; Get ptr to internal Cmnd Line repz movsb ; Move command line to internal store mov byte ptr[di],0dh ;append carriage return mov BX,1000H ; Release all but 1000H paragraphs mov AH,4AH ; ... MS-DOS 'Modify Allocated Memory' int 21H ; ... DOS Entry Interrupt call WalkTree ; Walk the tree recursively mov DX,offset EndMs1 ; Print out run statistics mov AH,9 ; ... MS-DOS 'Print String' int 21H ; ... DOS Entry Interrupt mov BX,DirCnt ; Display directory count in call PrintDecimal ; ... decimal mov DX,offset EndMs2 ; Display 2nd part of message mov AH,9 ; ... MS-DOS 'Print String' int 21H ; ... DOS Entry Interrupt mov BX,MaxLev ; Display maximum level in call PrintDecimal ; ... decimal mov DX,offset EndMsg ; Get ptr final part of message Terminate: mov AH,9 ; MS-DOS 'Print String' int 21H ; ... DOS Entry Interrupt mov DX,offset Path ; Restore directory to starting mov AH,3BH ; ... MS-DOS 'Change Subdirectory' int 21H ; ... DOS Entry Interrupt int 20H ; DOS Terminate Program ;========================================================================= ; WalkTree is a recursive subroutine that processes each level of the ; directory hierarchy. Each invocation of Walktree creates and uses a ; 50 byte stack frame containing the Segment and Offset of the prior ; level's DTA, the name of the current subdirectory, and a pointer to its ; own stack frame. WalkTree: mov SI,offset CurPat+3 ; Get current directory name mov DL,0 ; ... current disk mov AH,47H ; ... MS-DOS 'Get Current Directory' int 21H ; ... DOS Entry Interrupt mov SI,offset PatMsg ; Display Current directory call PrintString ; ... mov SI,offset PatTer ; Terminate Current directory call PrintString ; ... inc DirCnt ; Incr count of directories mov AX,Level ; Incr level inc AX ; ... mov Level,AX ; ... and store updated value cmp AX,MaxLev ; Update Maximum level, if necessary jbe WT1 ; ... Xfr - not necessary mov MaxLev,AX ; ... WT1: push BP ; Save old stack frame ptr sub SP,49 ; ... and get new stack frame mov BP,SP ; ... add BP,4 ; ... leave room for DTA adr push ES ; Save ES over DOS call mov AH,2FH ; MS-DOS 'Get DTA' int 21H ; DOS Entry Interrupt mov [BP-4],BX ; Save DTA offset and DTA segment mov [BP-2],ES ; ... in stack frame pop ES ; Restore saved ES mov DX,BP ; Set DTA to Stack frame mov AH,1AH ; ... MS-DOS 'Set DTA' int 21H ; ... DOS Entry Interrupt call CheckAbort ; Check for operator abort call Execute mov DX,offset MatAll ; Get ptr to ALL match string mov CX,10H ; ... set attribute for Subdirectory mov AH,4EH ; ... MS-DOS 'Find 1st Match' int 21H ; ... DOS Entry Interrupt jb PopLevel ; ... Xfr - Had error ProcessSub: test byte ptr [BP+21],10H ; Check for Subdirectory jz GetNextSub ; ... Xfr - not Subdirectory cmp byte ptr [BP+30],'.' ; Check for 'parent' or 'self' entries jz GetNextSub ; ... Xfr - 'parent' or 'self' mov DX,BP ; Get ptr to DTA add DX,30 ; ... and compute name ptr mov AH,3BH ; MS-DOS 'Change SubDirectory' int 21H ; ... DOS Entry Interrupt call CheckAbort ; Check for operator abort call WalkTree ; Walk the tree of new directory GetNextSub: mov AH,4FH ; MS-DOS 'Find Next Match' mov CX,10H ; ... set attribute for directory int 21H ; ... DOS Entry Interrupt jb PopLevel ; ... Xfr - error - no more matches jmp short ProcessSub ; Loop through directory PopLevel: mov DX,offset Parent ; Get ptr to 'Parent' string mov AH,3BH ; ... MS-DOS 'Change SubDirectory' int 21H ; ... DOS Entry Interrupt push DS ; Save DS mov DS,[BP-2] ; Restore prior DTA from stack mov DX,[BP-4] ; ... frame mov AH,1AH ; MS-DOS 'Set DTA' int 21H ; ... DOS Entry Interrupt pop DS ; Restore saved DS dec Level ; Decr directory level count add SP,49 ; Delete stack frame pop BP ; Restore stack frame ptr ret ; End of WalkTree ;------------------------------------------------------------------------- ;========================================================================= ; CheckAbort is used to check for an Operator Abort [any key pressed ; during execution. CheckAbort: mov AH,0BH ; MS-DOS 'Check StdIn Status' int 21H ; ... DOS Entry Interrupt or AL,AL ; Check for Char ready jz CAExit ; ... Xfr - no char ready mov AH,08H ; MS-DOS 'Console In, No Echo' int 21H ; ... DOS Entry Interrupt mov DX,offset AbtMsg ; Get ptr to 'abort' message jmp Terminate ; ... and terminate program CAExit: ret ; End of CheckAbort ;------------------------------------------------------------------------- ;========================================================================= ; Execute is used to execute the program specified on WalkTree's Command ; line. It uses MS-DOS Function 21H, SubFunction 4BH [Exec] to execute ; COMMAND.COM as a child. It searches the Environment to find COMSPEC ; in order to call COMMAND.COM Execute: push BP ; Save caller's registers push DS ; ... push ES ; ... push ES ; Save ES over CALL mov AH,2FH ; MS-DOS 'Get DTA' int 21H ; ... DOS Entry Interrupt mov DTASeg,ES ; Save DTA segment mov DTAOfs,BX ; ... and Offset pop ES ; Restore saved ES mov AX,CS ; Get segment for DOS 4B mov ParBlk+4,AX ; ... and store as Command Tail Seg mov ParBlk+8,AX ; ... and as FCB 1 Seg mov ParBlk+12,AX ; ... and as FCB 2 Seg mov ParBlk+2,offset CmdTail ; Store offset of Cmnd Tail mov ParBlk+6,5CH ; ... and offset of FCB 1 mov ParBlk+10,6CH ; ... and offset of FCB 2 mov DI,offset ComSpc mov bx,[ds:2ch] ;get environment string segment mov ParBlk,BX ; ... to Parameter Blk for DOS 4BH call FindComSpec ; Search environment for COMSPEC jnc GotComSpec ; ... Xfr - found COMSPEC mov AX,CS ; Set DS to local data space mov DS,AX ; ... mov dx, offset ComCom ;get ptr to 'command.com' jmp short goexec GotComSpec: mov di,offset comand ; dest offset of comand in di mov cl,65;large enough number smov1: lodsb ;load byte in al stosb ;store byte in comand or al,al loopnz smov1 mov AX,CS ; Set DS to local data space mov DS,AX ; ... mov dx,offset comand;file name to execute goexec: mov BX,offset ParBlk ; Get ptr to Parameter Block for DOS 4BH mov CS:SaveSS,SS ; Save Stack Segment & offset over mov CS:SaveSP,SP ; ... Exec call mov AX,4B00H ; MS-DOS 'Load & Execute Program' int 21H ; ... DOS Entry Interrupt cli ; Inhibit interrupts mov SS,CS:SaveSS ; Restore Stack Segment & mov SP,CS:SaveSP ; ... Offset sti ; Enable interrupts mov DS,CS:DTASeg ; Restore local data space mov DX,CS:DTAOfs mov AH,1AH ; MS-DOS 'Set DTA' int 21H ; ... DOS Entry Interrupt pop ES pop DS pop BP ret ; End of Execute ;------------------------------------------------------------------------- ;========================================================================= ; FindComSpec is used by Execute to locate COMSPEC in the Environment and ; the name of COMMAND.COM to pass to MS-DOS 21H, SubFunction 4B [Exec]. FindComSpec: mov DS,BX ; Set data space to Environment mov DI,offset ComSpc ; Get ptr to 'COMSPEC' for search sub SI,SI ; Start at relative 0 in Environment mov CX,7 ; Get length of 'COMSPEC' XFCS3: lodsb ; Get byte from Environment or AL,AL ; Check for end of entry jnz XFCS4 ; ... Xfr - not end of entry cmp byte ptr [SI+1],0 ; Check for end of Environment jz XFCS5 ; ... Xfr - end of Environment XFCS4: call UpCase ; Convert to upper case and mov [SI-1],AL ; ... store back in Environment cmp AL,'=' ; Check for '=' as in 'COMSPEC=' jnz XFCS3 ; ... Xfr - not '=' push SI ; Save both ptrs and length push DI ; ... push CX ; ... sub SI,2 ; Back up SI to end of string std ; Set Direction Flag [reverse] repnz cmpsb ; Compare Envirn string to 'COMSPEC' cld ; Clear Direction Flag [forward] pop CX ; Restore length and both ptrs pop DI ; ... pop SI ; ... jnz XFCS3 ; Xfr - did not match 'COMSPEC' clc ; Clear CARRY for good return ret XFCS5: stc ; Set CARRY for error return ret ; End of FindComSpec ;------------------------------------------------------------------------- ;========================================================================= ; UpCase is a utility subroutine to convert the lower case alpha char in ; AL to upper case. Only lower case alphas are affected, any other char ; in AL is returned unmodified. UpCase: cmp AL,'a' ; Check upper bound of lower case jb UCExit ; ... Xfr - not lower case - too low cmp AL,'z' ; Check upper bound of lower case ja UCExit ; ... Xfr - not lower case - too high and AL,0DFH ; Convert char to upper case UCExit: ret ;End of UpCase ;------------------------------------------------------------------------- ;========================================================================= ; PrintDecimal is a utility subroutine used to convert the 16-bit integer ; in BX to decimal and display it on StdOut as a 5-digit figure with ; blank suppression of leading zeros. It is overkill for the current ; version of WalkTree. PrintDecimal: mov CL,0 mov DX,10000 ; Get 10,000s digit and display call PrintDigit ; ... it mov DX,1000 ; Get 1,000s digit and display call PrintDigit ; ... it mov DX,100 ; Get 100s digit and display call PrintDigit ; ... it mov DX,10 ; Get 10s digit and display call PrintDigit ; ... it mov CH,BL ; Display units digit [no zero jmp short XPD2 ; ... suppression] PrintDigit: mov CH,0FFH ; Initialize result XPD1: inc CH ; Incr result sub BX,DX ; Divide by repetitive subtraction jnb XPD1 ; ... Xfr - not there yet add BX,DX ; Correct for overshoot cmp CH,0 ; Check result for zero jnz XPD2 ; ... Xfr - not zero result test CL,1 ; Test for leading zero jnz XPD2 ; ... Xfr - not leading zero ret XPD2: push DX ; Save divisor mov DL,CH ; Move digit to DL for DOS add DL,'0' ; Convert digit to ASCII mov AH,2 ; MS-DOS 'Console Output int 21H ; ... DOS ENtry Interrupt pop DX ; Restore divisor mov CL,1 ; Turn OFF zero suppression ret ; End of PrintDecimal ;------------------------------------------------------------------------- ;========================================================================= ; PrintString is a utility subroutine to display a NULL-terminated ASCII ; string on StdOut. On input, SI contains the address of the string to ; be displayed. All other registers are preserved. PrintString: push AX push DX PS1: lodsb or AL,AL jz PSExit mov DL,AL mov AH,02H int 21H jmp short PS1 PSExit: pop DX pop AX ret ;End of PrintString ;------------------------------------------------------------------------- ;========================================================================= ; Stack space. Since each invocation of the WalkTree subroutine creates a ; 50 byte stack frame on this stack, 3000 bytes of stack would allow for ; approximately 60 levels in the directory hierarchy, probably extreme ; overkill. STACK EQU $+3000 cseg ends end Start